Hydraulic control system



6 Sheets-Sheet l Dec. 22, 1964 J. MERCIER ETAL HYDRAULIC CONTROL SYSTEM Filed June 22, 1962 Dec. 22, 1964 J. MERCIER ETAL HYDRAULIC coNTaog. SYSTEM s sheets-sheet Filed June 22, 1962 INVENTORS 7544/ Maze/6,2 aen/4e@ Mae/e J. MERCIER ETAL HYDRAULIC CONTROL SYSTEM Dec. 22, 1964 6 Sheets-Sheet 3 Filed June 22. 1962 Dec. 22, 1964 x. MERCIER ETAL HYDRAULIC CONTROL SYSTEM 6 Sheets-Sheet 4 Filed June 22, 1962 da@ 4M m Dec. 22, 1964 J. MERCIER ETAL HYDRAULIC coNTRoL SYSTEM 6 Sheets-Sheet 5 Filed June 22, 1962 e 2 wi T 5 MZ w n MM@ .m 4 i .l JM a NmN Nm. .w

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EN www lwmw|| III Dec. 22, 1964 J. MERCIER ETAL HYDRAULIC CONTROL SYSTEM 6 Sheets-Sheet 6 Filed June 22, 1962 United States Patent fitice 3,162,014 HYBRAULIC CNTRL SYSTEM .lean Mercier, 1185 Park Ave., New York, NX., and

Bernard Mercier, New York, N.Y.; said Bernard Mercier assigner to Mercier @iaer Patent Corporation, Wilmington, Dei., a corporatien of Delaware Filed June 22, 1962, Ser. No. 204,328 Claims priority, application France Dec. 26, 1961 28 Claims. (Cl. 60--51) This invention relates to the art of hydraulic control systems, more particularly of the type to effect remote control of the rudder shaft of a ship.

As conducive to an understanding of the invention it is noted that where the rudder shaft of a ship requires considerable force for actuation thereof through an appreciable range of movement and with sufficient rapidity to correct the course of a large ship for relatively large deviation from on course direction, where low power uid under pressure is applied to actuate the rudder shaft from its neutral on course position by the manual rotation of the steering wheel, it will be ineffective for this purpose.

Where a large amount of force is applied upon initial rotation of the steering wheel, the rudder will swing considerably from its neutral position rendering it difficult to provide smooth correction to on course movement of the ship.

It is accordingly among the objects of the invention to provide a hydraulic control system which is relatively simple ia construction and dependable in operation and which upon operation of a control member, will effect relatively slow initial movement of a controlled member from its neutral position and thereupon with continued movement of said controlled member will apply relatively great force thereto to effect continued movement of said controlled member in the same direction as its initial movement. Y

Another object is to provide a system of the above type in which the initial movement of the controlled member is effected by the manual pumping of fluid and the subsequent movement is effected by the application of a relatively high power source.

Still another object is to provide a system of the above type in which a plurality of sources of uid under pressure are provided so that upon failure of one of said sources, the other will -be available to effect the desired movement of the controlled member.

According to the invention these objects areI accomplished by the arrangement and combination of elements hereinafter described and more particularly recited in the claims.

In the accompanying drawings in which are shown one or more of various possible embodiments of the several features of the invention,

FIG. 1 is a diagrammatic view of one embodiment of the invention;

FIG. lA is a diagrammatic representation of a conventional telemotor and reversing valve.

FIG. 2 is a diagrammatic view on an enlarged scale of a portion of the system of FIG. 1 showing particularly the hydraulic reversing valve in section;

FIG. 3 is a detail sectional view showing the control valve employed in FIG. 1;

FIG. 4 is a view similar to FIG. 1 of another embodiment of the invention useful for larger ships;

FIG. 5 is a longitudinal sectional view showing the control valve used inthe embodiment of-FIG. 4;

FIG. 6 is a view similar to FIG. 5 of the reversing valve of FIG. 4; Y

FIG. 7 is a view similar to FIG. l of still another em- Patented Dec. 22, 1964 bodiment of the invention useful for still larger ships, and

FIG. 8 is a view similar to FIG. 1 of another embodiment of the invention useful for smaller ships.

Referring now to the drawings, the hydraulic equip-j ment shown in FIG. l is designed, for example, to control the rudder shaft 11 of a ship.

To this end, the rudder shaft 11 has secured thereto and extending at right angles therefrom, a rudder bar 12 to which hydraulic actuators 13 and 14 are connected.

The actuators 13 and 14 which are identical, are positioned in substantially the same plane as the rudder bar on each side of the shaft 11. Each of the actuators comprises a cylindrical casing 15 pivoted at one end as at 16 to a fixed support 17. Slidably mounted in the casing 15 is a piston 18 which has secured thereto a piston rod 19 which extends through an opening 21 in one end of the casing 15.

The free end of each of the piston rods 19 is pivotally connected as at 22 to the top surface of the rudder bar 12, the pivots 22 being equally spaced from the axis of the shaft 11. One end of the rudder bar has a longitudinal extension 23 to the undersurface of which is pivotally connected as at 24 the end of a piston rod 25. The piston rod 25 is connected to the piston 26 of an additional hydraulic actuator 27, which comprises a cylinder 28 having an opening at one end through which the piston rod extends and pivotally connected at its other end as at 29 to a fixed support. The additional hydraulic actuator 27 is also in substantially the same plane as the rudder bar 12 and in the neutral position shown, the pivotal mount 29 of the additional actuator 27, the pivots 24 and 22 and the shaft 11 are all in longitudinal alignment.

To control the hydraulic actuators 13, 14 and 27, a relatively low power pressure source 31 of fluid and a high power pressure source 32 of iuid are provided.

The low power pressure source 31 comprises, for example, a tele-motor which may be mounted on the deck of the ship and may include a pump (not shown) controlled by the steering wheel 33. When the steering wheel is turned in one direction, fluid under pressure will flow, for example, vthrough line 34 and be returned through line 35 and when the steering wheel is rotated in the opposite direction, the fluid will flow through line 35 and return through` line 34.

The lines 34 and 35 are connected respectively to junctions 36 and 37 which in turn are connected respectively to lines 3S, 39 to the pressure ports 41 and 42 of a hydraulic control valve 40.

The valve which is clearly shown in FIG. 3, has four additional ports 43, 44, 45 and 46, which are controlled by slidable valve members 47, 48.

Thus, when fluid under pressure is applied say to port 42 and the valve member 47 is moved to the right' from the neutral position shown, the ports 45, 46 will be connected through the passageway 49 in valve 40 and the ports 43, 44 will be connected through passageway 50 in valve member 47. When fluid under pressure is applied to port 41 to move the slidable valve member 47 to the Y left from the neutral position, the ports 43, 46 will be connected and the ports 44, 45 will be connected, the pressure port 46 being effectively closed when valve member 47 is in the neutral position.

Flow of uid under pressure from pressure source 32 which is connected to pressure port 46 by line 63 may in addition to being controlled by telemotor 31, also be controlled by two solenoids 51 and 52, which illustratively form part of Valve 40. The solenoids are controlled byl leads 53 and 54 connected to a switch 55, positioned on the deck of the ship adjacent the steering wheel 33. The switch is of the type that when in its neutral or central aisaoia position, both of the solenoids will be :ie-energized and when the switch is moved to one side of the neutral position, the solenoid 51, for example, will be energized and when the switch is moved to the other side of the neutral position, the solenoid 52 Will be energized.

Thus, referring to FIG. 3, when solenoid 52 is energized, the plunger 56Vthereof will move to the left moving valve member 48 to the left against the force exerted by 'spring 57.

When this occurs, even though the valve member 47 is in neutral position, pressure port 46 will be connected by passageway 58 to the chamber C on the left side of valve member 47. As a result, the valve member 47 will be moved to the right connected ports 45, 46 and ports 43, 44.

VWhen solenoid 51 is energized, the plunger 59 thereof will move to the right, moving valve member 48 to the right against the force exerted' by spring 61.

As a result, pressure port 46 will be connected by passageway 62 to chamber C on the right side of valve member 47. Consequently, valve member 47 will be moved to the left, connecting ports 43, 46 and 44, 45.

The pressure source 32 of iiuid under pressure, to which the port 46 of the hydraulic valve 40 is connected by line 63 may be of any conventional type, and the port 44 isv connected by line 66 to the reservoir R for return of fluid, said reservoir illustratively being part of the pressure source 32.

The ports 43, 45 of the valve 40 are connected respectively by lines 67 and 68 to ports 69 and 71 leading into the actuators 13, 14 between the pistons 18 and the pivoted ends 16 thereof. The junctions 36 and 37 arey connected by lines 72 and 73 to ports 74 and 75 leading into the actuators 13, 14 on the other side of the pistons, 18, i.e., into the annular chambers 76 formed by the piston rods 19. 1n addition, the lines 72 and 73 are also connected to the inlet ports 77 of shock absorbers 78 which are identical. Thus, the shock absorbersY cornprise a Ycylinder closed at one end and having the port 77 at its other end, said cylinder having a piston 79 slidably mounted therein and urged toward port 77 by a spring S1, the tension of which may be adjusted by turning knob 80.

The ports 69 and 71 are alsoy connected by lines 82 and Y83 to junctions 84 and 85 and through one-Way check valves 86 and 87 to line 88. The check valves are designed to permit iiow of fluid only from ports 69 and 7.1 towardline `8S. The line 38 is connected through pressure relief valve 89 to reservoir R, said reliefvalve 89 being designed to open when the pressure exertedv thereagainst. exceeds a predetermined amount.

Y The junctions 84 and85 are connected by lines 92 and 93 to the ports 94 and 95, 96 respectively, ofy a reversing valve 98 FIG. 2), said valve having two additional ports 99 and 101 connected by lines 162 and 193 to lines 104 and 105.V The lines 104, and 105 areconnected to the ports 106 and 197 on leach side of piston 26 of hydraulic actuator 27 and also through one-Way check valves 108 and 109 to line S8, said check valves permitting 110WA only in direction from ports166 and 107 to the relief valve 89.

The valve 98 (FIG. 2) 111 controlling the ports thereof and in the neutral position Aojjtlfre valve, member, Viiow'through.the ports is cut off. To effect movement of the valve member 111, the hydraulic cylinder 27 has secured thereto and rigid therewith a curved actuating arm 112 which has a reduced portion 113 at its free end defining an inclined Vcamming surface 114. AIn the neutral position shown of the hydraulic actuator 27, a roller 115 at the end of the extension 116 of tllievalve member 111`Will be retained against, say,

the mid portion of camming surface 114 by spring 117 to;

retaink the valve member 111 in the neutral position shown. When the hydraulic actuator 27 is pivoted in a counterclockwise direction from the position shown in FIG.' 1,

has a slidable valve memberv as the roller 115 rides down cam surface 114, the slidable valve member 111 of valve 98 will be moved to the left to connect ports 94, 161 and 95, 99 and when the hydraulic actuator 27 is pivoted in a clockwise direction from the position shown, as the roller 115 rides up cam surface 114, the slidable valve member 111 will be moved to the right to connect ports 94, 99 and 96, 161.

Operation, FIGS. 1-3

In the operation of the equipment shown in FIGS. l to 3, assuming that the ship is steering a straight course with the rudder thereof aligned with the longitudinal axis of the ship 'and with the rudder bar 12 at right angles to the longitudinal axis of the ship, with the valve 4t? in its neutral position, all of the ports 46, 43, 44 and 45 will be closed and hence no Huid under pressure will be iiowing through the line 63. With the switch in the neutral position shown, the solenoids 51 and 52 will be cle-energized.

Assuming that it is desired t-o move the rudder shaft in a clockwise direction from the position shown, the steering Wheel 33 of the Vtelemotor 31 is turned by the helrnsman in direction to force fluid from the pump (not shown) controlled by the steering wheel 33 through line 35. As a result, fluid under pressure will flow through such line 35 to junction 37 and to port 42 of the valve 4t! as well as to port 75 leading into the annular chamber 7,6 of hydraulic actuator 13.

The application of vpressure to port 42 will cause the valve member 47 of valve 41B to move to the right, connecting ports 46, 45 and ports. 43, 44. As a result of lthe connection of ports 45 and 45, fluid under pressure will be supplied from the power source 32 through line 63, connected ports 46, 45 to port 71 of actuator 14 and to line d3.

Application of fluid under pressure to port 71 of lactuator 14 will cause the piston thereof and hence the piston rod 19 toV move outwardly, the uid in annular chamber 76 of said actuator 14 flowing from port 74 through line 72 and return line 34 back to the pump of the telemotor 31. Due to .the `outward movement of the piston rod 19 of actuator 14 which reacts against the rudder bar 12, the rudder bar will be moved in a clockwise direction from the position shown in FIG. 1.

Fluid under pressure is applied to the port 71 of actuator 14 so long as the valve 4i! has had its valve member 47 moved to the righ-t by the application of pressure iiuid to port 42 thereof which continues so long as the helrnsman rotates the steering wheel 33.

As the rudder Vbar 12 moves in a clockwise direction, the actuator 27 will be pivoted in a counterclockwise direction about its pivot 29. Consequently, the pivotal connection of the piston rod 25 of actuator 2.7 to the rudder bar will move out or" longitudinal alignment with pivots 29 and 22 and hence the actuator 2.7 will now be capable of exerting force against the rudder bar 12.

Referring to FG-S. 1 and 2, prior to movement of actuator 27, the valve member 111 of valve @d Witt maintain the ports 94, g5, 96 in closed position. As soon as the actuator 27 starts to pivot in a counterclockwise direction,

' the roller 115 will ride down the inclined surface 114 pery providing additional force to that exerted by the movement of the piston rod 19 of actuator 14. The uid in actuator 27 to the right of thel piston 26 thereof wilt be Vforced through port 167 and lines 195, MP3, through the ports 1%1 and 94 `of valve 9S and lines 92, 82, 67 through ports 43 and 44 of vaive 4i? back to the reservoir R.

Assuming, at this time, the hel-msman .st-ops rotating the steering wheel 33, at this time valve means in the lines 34, from the telemotor will close and immediately there will no longer be any fluid under pressure supplied through line 35 or returning through line 34.

The valve means in the lines 33, 35 and associated circuitry of the telemotor are conventional and are diagrammatically shown in FIG. 1A.

Thus, the steering Wheel 33 controls a pump P which has its inlet connected to reservoir R and its outlet connected :to port P-l of valve V and the ports P-2, P-3 of valve V are connected to each other and to reservoir R.

The valve V has two additional portsCP-4, P-S connected to lines 34, 35 respectively. The movable valve member VM of valve V which is of the conventional reversing type is normally retained in neutral position by coil springs S and the valve member VM is movable to either of two extreme positions by solenoids SL.

In the neutral position of the valve, ythe -ports thereof are closed. In one extreme position, ports P-1, P-4 and P-2, P5 are connected so that iluid -under pressure will be applied to line 34 and returned through line 35 and in the other extreme position ofthe valve ports P-l, P-S and P-3, P-4 are connected so that fluid under pressure will be applied to line 35 and returned through line 34.

The steering wheel of telem-otor 31 when rotated operates pump P which forces fluid under pressure, from reservoir R Ito port P-l. In addition, when steering wheel 33 is rotated, it actuates conventional control circuits in casing C, to energize either of the solenoids SL depending upon the direction of rotation of the steering wheel, the solenoids being automatically deenergized when no rotation is imparted to the steering wheel so that the valve will immediately return to neutral position.

As the construction and operation of such telemotor is conventional and per se forms no part of the invention, it will not be further described.

Due to the fact that at this moment the ports 46, 45 of Valve 4i) will still be connected, there will still be additi-onal lluid under pressure from source 32 applied to port 71 of actuator 14 as well as to port 106 of actuator 27 so that the movement of the rudder bar 12 in a clockwise direction -will continue slightly causing the piston 18 of actuator 13 to move further toward the closed end of the actuator 13. Since no additional fluid under pressure is being applied to port '7 5, connected to the annular chamber 76 of actuator 13, such further movement of the piston 18 of actuator 13 will increase the volume of the annular chamber 76 of actuator 13 and hence permit the iluid in line 39 leading into port 42 of the valve 49 lto flow into the annular chamber 76 so that the valve member 47 of valve 4l) will immediately return to its neutral position due to the pressure in lines 72, 38 from actuator 14 closing the ports 46, 43, 44 and 45.

As the result of the closure of such ports, the source of fluid from the power source 32 will immediately be cut off so that no further movement will be effected of the piston rods 19 and 25 of actuators 14 and 27 and hence no lfurther movement will be imparted to the rudder bar 12.

It is to be noted that the return of valve 40 to its neutral or closed posi-tion occursalmost immediately after rotation of the steering wheel is stopped.

that luid from the pressure source 31 will be supplied v as desired to eifectthe steering action.

pressure will flow from the power source 32 through line 63, ports 46, 43 to port 63 of -actuator 13 and also through lines 82 and 92, ports 94 of valve 98 which is in communica-tion with port 101, lines 103 and 105 to port 107 of actuator 27.

Consequently, the piston rod 19 of actuator 13 will move outwardly reacting against the rudder bar 12 to rotate the latter in 4a counterclockwise direction and in addition, since the piston rod 25 of actuator 27 will move inwardly, additional force will =be exerted against the rudder bar 12 to effect such movement in a counterclockwise direction. So long as the helmsman rotates the steering wheel in such desired direction, the valve 40 will remain open and the piston rod 19 of actuator 13 will move outwardly and the piston rod 25 of actuator 27 will move inwardly. When the rudder bar 12 has been moved sufficiently so that it is in the neutral position shown, at which time the actuator 27 will be longitudinally aligned with the rudder bar 12, the actuator 27 will no longer have any effect on .the movement of the rudder bar and at this time the valve 98 will be in closed position as shown. When the rudder bar is in neutral position, which is readily determined Iby the helmsman by a suitable indicating mechanism which is conventional, and hence is not shown, he will stop rotation of the steering wheel.

As previously described, the continuation of the application of fluid under pressure through the open valve 40 to actuator 13 will cause the piston rod 19 of actuator 14 to move inwardly an additional amount, thereby relieving the pressure :on the line 38 connected to port 41 so that the slidable valve member 47 thereof will return to neutral position thereby closing the ports 46, 43, 44 and 45. y

With the arrangement shown in FIG. l, the rudder shaft 11 may be rotated through an angle of 90 from the neutral position shown. Thus, even though the hydraulic actuators 13, 14 alone will provide but little force when they have moved the rudder bar in either counterclockwise or clockwise direction, to an angle approaching due to the relatively small lever action then provided, the addition of the hydraulic actuator 27 reacting against the rudder bar will provide suicient force to effect movement of the rudder bar through such angle of 9G.

In the event that the telemotor 31 should be disabled, the steering Iaction may still be effected by the electrical controls provided.

Thus, with the telemotor disabled and no fluid under man rmay merely lmove the switch 55 to the left or right Thus, if the .switch is moved from the neutral position to left or right, either the solenoid 51 or 52 will be energized to effect movement of the slide member 48, thereby connecting the ports 46, 43, 44 and 45 in the same manner as if the valve member-47 was actuated by fluid under pressure applied to the ports 41 or 42.

In the event, while the ship is sailing, a wave should strike the rudder causing the latter to move suddenly, in either a clockwise vor counterclockwise direction, means are provided to prevent injury to the hydraulic system.

Thus, assuming that the rudder is moved in a clockwise direction, and due to the impact of a wave against the rudder, the piston rod 19 of actuator 14 is moved outwardly the piston rod 19 of actuator 13 will move inwardly. As the piston rod of actuator 14 moves outwardly, the iluid in annular chamber '76 thereof will pass through the port 74 into the port 77 of the shock absorber '78 reacting against the spring urgedpiston 79 therein to take up the surge of pressure. At the same time as the piston rod of actuator 13 moves inwardly, the fluid under pressure will pass through port 69 and line 82 reacting against check valve S6, forcing the latter olf its seat and reacting against the relief ,valve 89 which is set to open at a predetermined pressure to bleed the fiuid into the reservoir R. Similar action will occur when the rudder is suddenly moved by the impact of a wave in a counterclockwise direction.

` identical as shown.

In the event that the main power supply 32 should fail, the ship is still capable of being steered under the action'.

of the `fluid under pressure from the telemotor 31 which,l

depending upon the rotation of the steering wheel, is, forced into the por-ts 75 and 74 respectively of actuators,y

Y13 and 14.

Thus, when fluid under pressure is applied through line 35 of the telemotor and it enters the port 75 of actuator' '13, it will cause the piston rod 19 thereof to move in vwardly reacting against the rudder bar 12 to Imove the;

latter in a clockwise direction. At this time, since the: iiuid yunder pressure is also applied to port 42 of the valve: 46, the latter Will be actuated to connect ports 43, 44 to' provide return to the reservoir R of the liuid in the ch arnber D of actuator 13. As the piston rod of actuator 13 moves inwardly, the piston rod of actuator 14 will move: outwardly'and the `iiuid in annular chamber 76 thereof will tiow through port 74, lines 72 and 34 back to the tele motor to complete the circuit.

It is to be noted that the hand operated telemotor 31'. provides relatively low power to the system and the power source 32 high power to the system, such low power being'.

' sufficient for small corrections in the course of the ship.

In the embodiment shown in FIG. 4, the equipment isy designed to apply greater power to the rudder shaft than: that provided by the embodiment shown in FIGS. i to 3h Referring to FIG. 4, the telernotor 121 illustratively has two sources of fluid under pressure whichare com` trolled simultaneously by the steering wheel 122. Thus, 'when the steering wheel 122 is' rotated in one direction,y

iiuid underV pressure will he provided through linesr123y v and 124 and return of iluid will be provided through lines. 125 and 126.

rThe rudder shaft 127 of the ship, which is controlled 1 by the telemotor 121, has secured thereto a rudder bar 12S .and having a slidable piston 132 therein to which one end of the piston rod 129 is secured. As is clearly shown in FIG. 4, the cylinder of the actuator 131 is pivotally mounted as at 133 to a fixed support. When the rudder is longitudinally aligned with the axis of the ship, the rudderbar-IZS will, also -be so aligned and insuch position the Vpivot defined by shaft 127; the pivotrpoint 131?- and the pivot 133 of the actuator 131 will all extend along the same longitudinal line as is clearly shown in FIG. 4.

Pivotally connected to the undersurface of rudder bar 128 between its ends is one end of a link-13d, the other end of which is pivotally connected as at 135 to the end of arm I141) of a substantially L-shape'dfl'eve'r 136.y As shown in FIG. 4, the other arm 137 of the lever 136`is pivotaily mounted as at 138 between its ends, Pivotall'y connected as at 139 to the end of arm 137-.of lever 136 and to the arm137 on the other sideof the pivot 138 as at k141 (said pivotV points 139 and 141 being equaliy spaced from the pivot 138), are the free ends of the piston rods 142 of hydraulic actuators 143 and'144 which are The hydraulic actuators 143, 144 desirably are of the type shown in Patent No. 3,009,322 and each iilustratively comprises an'outer cylinder 145, in which is slidably mounted an inner cylinder 146' closed at one end as as Y' 147 and extending through an'ope'ning 148-in the outer end of cylinder V145. Slidably mounted in the inner cylinder 14el is the piston rod 142 which extends through anjopening 149 inthe outerend thereof. rEhev actuators 143`and 144 are pivotally mounted at their'ends -as at `151 toa fixed support and` extendin'substantially,a horizontal plane; the pivotal connection ot'said piston rods 14210 VleverV 136 being on the' undersurface thereof.

, An additional actuator 1'52is provided which comprises 'i 'l la cylinder positioned in substantiallyA ahorizron'rtal plane and pivotally connected at one end as at 153 to a fixed support. The actuator 152 has a piston 154 slidably mounted therein to which one `end of a piston rod 155 is secured, the other end of the piston rod 155 being pivotaiiy connected to the end of the lever 136 at the pivot on the undersurface of said lever.

The lines 123 and 124 from the telernotor 121 are connected to ports 156 and 157 leading into outer cylinder and piston rod 142 of actuator 143, said piston rod 142 illustratively being hollow and the lines 125 and 126 oi telemotor 121 are connected to ports 158 and 159 of actuator 144.

The ports 161 and 162 of actuator 152 leading into the cylinder thereof on opposed sides of the piston 154 thereof, are connected by lines 163'and 164 to junctions 165 and 166. Junctions 165 and 166 are connected by lines 167 and 168 to ports 169 and 171 of valve 172; by lines 173 and 174 to ports 175 and 176, 176 of the valve 177 (FiG. 6) which is similar to valve 98 (FIG. 2) and also through check valvesi173 and 179 to line 181, the check valves permitting flow in direction to line 181. The line 181 is connected to a pressure relief valve 182 which may be set to any predetermined value to discharge iiuid through return line183 to a reservoir R, illustratively in the power source S. The line 181 is also connected through one-way valves 184 and 185 and lines 186 and 187 to the ports 18S and 189 of actuator 131 and also to the ports 191 and 192 of valve 177, the cheek valves 184 and 185 permitting flow only in direction toward the relief valve 182.

The valve 177 has a spring loaded valve member 193 and is normally in position to close ports 175, 176, 176'.

rEhe extension 194 of valve member 193 has a roller 195 at its outer end which is retained against the mid portion of the inclined camming surface 196 of an actuating arm 197 when the rudder bar 123 is in the neutral position shown in FIG. 4. v As is clearly shown the actuating arm 197 comprises an elongated bar of reduced Width at one end as at 198 defining such camming surface 196.

The bar is slidably mounted through block bearings 198 and the end thereof is pivotally connected through link 199 to a iinger 291 rigidly secured to the end of rudder bar 128. v

Positioned on each side ofthe rudder bar 128 and in either a clockwise or a counterclockwise direction beyond an Vangle of say 35, in each direction, are the plungers 292 of microswitches 203 and 204.

These microswitches are in circuit with a switch 265 which may be mounted on the deck of a ship. The microswitches 263, 204 are electrically connected to the solenoids of valves 206 and 267. The valves are of the type that when de-energized, they will provide a path between ports 2128 and 209 thereof and` when energized the ports 268, 269 and 211 will beconnected. The ports 211 are connected by common return lineA 212 to one side of check valves 213, the other sides of which are connected to lines 124 ,and 12d Vfrom the telemotor, the check valves permitting flow only in direction from ports 211 to said iines 124 and 126. T he ports 239 of valves 2116 and 267 .are connected to lin-es 124 and 125. The valve 172 (shown in FIG. 5 has control ports 215, 216, and 217, 21Satl each end. The ports 215 and 217 are connected by lines 2153 and 221 to lines 125 and 123 and the ports 216, 21S are connected by lines 222 and 223 to ports 20S of vaives 297, 206.

T he valve 172 is of the type that in neutral position, as shown, the ports 169 land 171 thereof will be closed and when the valve member 224 thereof is moved upwardiy in the villustrative Vembodiment shown, the ports 225, 171 and 22,6, 169 will be connected and when moved lar to that shown inthe Vembodiment otFIG. 1 and the g ports 226, 226 are both connected to "return line 229 which leads to the reservoir.

Operation, FGS. 4-5

In the operation of the equipment shown in FIG. 4 and FIG. 5, lassuming the ship is at sea, in order to provide a safeguard against a 90 turn at full speed which could break the rudder shaft, the switch 265 is closed so that the microswitches 203, 264 and valves 206, 207 are readied for operation.

When .the steering wheel 122 of the telemo-tor is turned in one direction, say to apply uid under pressure through lines 123, 124, such iluid will enter ports 156, 157 of actuator 143. As the chambers ii and of actuator 143 are supplied simultaneously with substantially equal pressures, there will exist in the chamber 0 a pressure sufiicient to elongate the assembly 146-142 with a given force and in chamber il a pressure capable of displacing the said yassemblies 146-142 toward a position corresponding to the complete extension of the apparatus with a force greater than that bringing about the elongation of said assembly 146-142 due to the fact that the diameter of the cylinder 146 is greater than that of member 142.

As a result, the piston rod 142 will be moved outwardly reacting against the end of lever 136 causing the ilatter to tend to rotate in a counterclockwise direction'.

At the same time, such pressure iluid will be applied through ylines 12S-221 to port 217 of valve 172 and through line 124, communicating ports 209-208 of valve 206, line 223 to port 218 of valve 172.

As a result, the valve member 224 (FIG. of valve 172 will be moved upwardly to connect ports 22S-171 and 226-169.

As a result of such connection of .the ports, iiuid under pressure will be supplied from power source S, line 228, port 22S-171, lines 168, 164 to port 162 of actuator 152 to move the piston rod 155 thereof inwardly thereby reacting against the lever 136 to urge the latter in a counterclockwise direction and through the link 134 causing a corresponding countercloekwise rotation of the rudder bar 128.

ln addition, uid under pressure will be applied from line 168 to junction 166, and through line 174 to ports 176, 176 (FIG. 6) of valve 177 which initially is in closed position.

Due to the initial movement of the rudder bar 128 in a counterclockwise direction, bar 157 will be moved to the right causing the .roller 195 of valve 177 to roll down the inclined camming surface 196 so that the valve member 193 of valve 177 will move downwardly connecting ports'176-192'and 175-191. As a result, luid under pressure will ow into port 18S? of actuator 131 lifting the piston rod 129 thereof which will react against the end 130 of rudder bar 128 also urging the latter in a counterclockwise direction.

When the rudder bar swings through an angle of say in a counterclockwise direction, it will engage the micro switch 203 thereby completing a circuit through closed switch 265 to solenoid valve 266. As a result, the

ports 298, 269 of valve 266 will be connected to port 211 of said valve 206.

, excessive stresses, and the relatively slower movement of the rudder past the 35 position will have no dangerous effect on ships sailing at high speed.

Where it is desired to effect larger more rapid angullar 10 movement of the rudder when the ship is moving slowly such as when docking, it is merely necessary to retain switch 205 in open position so that valve 206l will not be energized when microswitch 203 is engaged.

As soon as the helmsman stops rotation of the Wheel 122 no further fluid under .pressure will be applied to ports 156, 157 of actuator 143, nor to ports 217 or 21S of valve 172. As a result, due to the force'o-f coil spring 230 at the upper end of valve member 224, the latter will be moved downwardly, to close ports 169-171 so that no further uid under pressure will be applied from source S to actuator 131, 152 and hence the rudder bar will remain in set position until the helmsman turns the wheel 122 in the opposite direction.

ln the event that one of the fluid sources from telemotor 121 should fail, i.e., if no fluid under pressure should flow through line 123 to port 217 of valve 172, the fluid under pressure from line 124 to port 218 will stiil effect movement of the valve member 224 and also such pressure lfrom line 124 to port 157` of actuator 143 will still eiect outward movement of piston rod 142-.

In the event that the power source S should fail, steering at reduced speedcan still be eected. Thus, the lluid from the telemotor applied to .actuators 143, 144 will provide outward movement of the piston rods 142 thereof Ias desired for movement of lever 136 and rudder bar 128, the cheek valves 184, 185 permitting movement of the piston rod of actuator 131 and the check valves 17S, 179 permitting movement of the piston rod of actuator 152, so that said actuators will not interfere with movement of the rudder bar by the actuators 143, 144 alone.

Where, when the ship is to be docked, it is desired to rotate the rudder to make use of an auxiliary docking propeller carried by the rudder, it Iis merely necessary to open switch 205 so that microswitches 203, 204 will not be operative. l

On large ships, hand operation by a manually operated telemotor is not feasible even at low speed, due to the great torque required to move the extremely large rudder employed.

The equipment shown in FIG. 7 is desirable in such case.

As shown in FIG. 7, the equipment comprises a power source S' which comprises a reservoir 251, having a partition 252 rising illustratively one-half of the height thereof defining two chambers A, B. The inlets of two constantly driven pumps 253, 254 are connected respectively to said chambers A, B and the inlet of a normally deenergized standby pump 255 is also connected to chamber A.

The outlets of said pumps 253, 254, 255 are connected to common line 256 and a normally open solenoid valve 257 having ports'261, 262 is interposed in said line between pumps 253, 254.

Mounted in the reservoir above the partition 252 is a K iloat switch 258 which is designed to actuate the valve The line 256 on the side thereof connected to port 261 of valve 257 is connected to port 271 of a valve 272, the latter having two additional ports 273, 274. The

valve 272 has a controlport 270 connected to pressure switch PS and to the fluid port of pressure accumulator 275. The pressure switch controls pump 255 to energize the latter if the pressure in the accumulator should fall below a predetermined value. Port 273 is connected to Ythe fluid port of pressure accumulator 275 and to the port 276 of normally closed solenoid valve 277.

Port 274 of valve 272 is normally connected to port 271 when the accumulator is charged and said port 274 of rod 291 is connected as at 293 to one end of a pivoted actuating lever 294 which, when moved to the left or v right of neutral position, will actuate the valves 265, 285.

.In addition, each valve has a pressure port 295, 296 at each end to permit hydraulic actuation thereof in the manner to be described.

The valves 265, 285 mayalso be actuated by an electric motor 297,v the shaft of which, through an electric clutch 297 drives a pinion 29S which in turn drives a rack 299 connected to lever 294.

Thus, the servo valves 265, 285 may be operated manually by leverj 294, hydraulically by uid applied to ports T295, 296 or. electrically by motor 297.

The ports 268, 269' and' 289, 238 of valves 265, 285

`are connected respectively to the ports 362, 361 of hydraulic actuators 393, 304- on each side'of the piston 335 thereof. Each actuatoris pivotally mounted at one ,end as at 306 and has a piston rod 3127 secured to the piston 3G5thereof and pivotally connected as at 308 to a rudder bar 309 on each side of the rudder shaft V311 to which lthe rudder bar is secured.

One endfof the rudder bar 309 is pivotally connected as at 312 to the outer end of the piston rod 313 of khy- "draulic actuator 314.

Actuator 314 is pivotally mounted at one end as at 315 and has a piston 316 slidable therein f to which the piston rod 313 'is secured.

Theactuator 314 has a curved actuating arm 317 secured thereto which has a reduced portion 318 defining an inclined camming surface 319.

A valve 321 similar to valve 98 in FIG. 2, has a roller 322-secur`ed to the valve member thereof, which roller when the 'pivots :308, 312 and 315 are longitudinally aligned, rests on the mid portion of said inclined surface.

The valve 321 has ports 323 and'324 connected to lines 325, 326 connected to ports 288, 289 of valve 285 and ports 32,7, 328 vconnected to ports 331, 332 on each side of the ypiston 316 of actuator 314.

Secured to actuator 314fand extending beyond ythe c pi'voted end"315 thereof is a bar 333 against which rests the ends- 334 of the piston rods 335 of hydraulic actuator 336; 337,'theends' 334 being equally spaced on each side of the pivot 315.

The actuators 336, 337 are rigidly secured and each has a port 338 at the closed end Vthereof connected by lines 1339 341 to telemotor 342. In addition, lines 339 'and -3'49 are connected to 4ports 295, 296 of valves 2,65,

285respectively.

Operation, FIG. 7

. In the operation of the equipment shown in FIG. 7

before the accumulator 275 is charged, the valve 272 ,-will be in position connecting ports 271 and 273 and the f pressure switch PS will complete the circuit to pump V255.' When the main power switchlnot shown) is closed, the Y.pumps 253, 254 and 255 will be energized;

A(peration of'pump 255 will charge the accumulator -throughconnected ports 271, 273 of valve'272 and when ythe accumulatoris charged, valve 272 will switch to con- *274.and the pressure switch will `cut'ol nect ports 271,

pumpv 255. l

. *At this 'time .fluid .WiL/11 Vaow from pumpszss, 254 through commonlines256 andlines283, 263l respectively to ports y284,.,26fifof valves 285, 265. v-As'the'se valves in the neutral position have ports 284, 286 and264, 266 connected, such'iluid willrow through the associated return lines. 287. andt267-backto the reservoir 251.

When. the. steeringk wheel 345 of the vte1emotor-3lt2 is Urotated', fluid under pressure will flow, say, through linev 336 to drop to zero.

Cil

339 to port 338 of actuator 336 and to port 295 of valve 265'.

. As a result 4of the tluid under pressure applied to port 295 of valve 265, the valve member of valves 265, 285 will move to the right and the ports 264, 263 and 266, 269 of valve 265 will be connected and the ports 286, 239 and 234, 288 of valve 235 will be connected.

Consequently, iiuid under pressure will be applied from both pumps 253, 254 to port 392 of actuator 393 (through valve 265) and to port 301 of actuator 394 (through Valve 285) so that the piston rods 397 of actuators 363, 3tl4 will respectivly push and pull against the ends of the rudder bar 309 to pivot the latter in a clockwise direction. This will pivot the actuator 314 in a counterclockwise direction to move the associated portion of bar 333 away from the end 334 of the piston rod 335 of actuator 336, said piston rod 335 following the bar due to the pressure applied to port 38 so long as the steering wheel 342 is being rotated.

As a result of the counterclockwise movement of actuator 314, the roller 319 of valve 321 will ride up the camming surface 322 of arm 317 thereby connecting ports 323 and 328 of valve 321 so that uid under pressure will flow into port 332 of actuator 31eto move its I piston rod outwardly to urge the rudder bar 339 in such clockwise direction.

If the helrnsrnan should stop rotation of Steering wheel 345, the flow through line 339 would stop. However, due to Ytlhe slight additional movement of the rudder bar 339 and hence the actuator 314 and bar 333, the latter would move away from the end 334 or" the piston rod 335k of actuator' 336 thereby causing the pressure in actuator However, the pressure in actuator 337 will increase as valves (not shown) in the telemotor 342 which closeV when the steering Wheel is not rotated, would close lines 339, 341 and hence such increase in pressure in actuator 337 would cause the valve member of valve 235 to move to the left. This would also cause the valve member of valve 265 to move to the left until both valves were in neutral position.

To restore the rudder bar to neutral position or to move it in a countercloclrwise ldirection from neutral position would merely require the steering wheel to be rotated in the opposite direction.

In order to shift from the hydraulic control effected by the operation of telemotor 342 to the electrical control, it is necessary to preventy interference by the hydraulic system including the lines 339, 3651 to the telemotor which are charged with oil.

To this end, lthe switch 351 is provided which, when closed, energizes the clutch 297y operatively to connect the pinion 298 to rack 299 and also energizes solenoid valve 352 to connect lines 339,L 341 to reservoir 251. Thereupon, the steering switch 353 may be moved to the left or right from neutral position to cause corresponding rotation of motor 297 and hence to move the rack 299 and the control lever 287 as desired.

It is to be noted that the accumulator T5 normally is not in the Vsystem but is connected into the system when valve 277 is energized.

This occur'swhen the valves 265, 285 are in the full open position which occurs only when there is. quick movement of the steering wheel 342, for example, which permits such vfull opening in an emergency condition.

Thus, a pairof contacts 355 are provided which are engagedby a movable contact 356 carried by the rack 299 when the latter is inthe two extreme positions.

At this time the accumulatorV would supply additional energy to that furnishedlby pumps 253, 254. 1f the accumulator was in circuit at all times, excess energy wouldk be furnished wit-h resultant unnecessary power consumption. Y

' vIt is desirable to have acon'tinuous system to both of Ythe actuators 363, 304 soi that they will operate uniforrnly.r lf the two pumps 253, 254 were connected to 13 I the associated actuators separately, jerky action might occur.

The system provides for such smooth actuation, yet provides security against failure of part of the hydraulic system.

Thus, in the event that there should he a break in line 263, for example, the level of the liquid in reservoir 251 would drop and the float would cause switch S to close valve 257 to isolated chambers A and B. As a result, the liquid in chamber A could not drop below the level of partition 252 and hence the pump 253 would still provide uid to the system which would still be operative although with less power.

In the embodiment shown in FIG. 8, the rudder bar A 400 is secured to the rudder shaft 401, which extends port 409, 410 leading thereinto adjacent such pivoted end 408.

The ports 409, 410 are connected by lines 411, 412 to junctions 413, 414 which are connected by lines 415, 416 to a telemotor 417 which has a steering wheel 418. Upon rotation of said steering wheel, fluid under pressure will be forced through one of the lines 415, 416 and returned through the other.

The junctions 413, 414 are connected by lines 421, 422 to -the ports 423, 424 of a valve 425, identical to the valve 9S shown in FIG. 2, said valve having additional ports 426, 427, 428. The valve member 429 of valve 42S in the neutral position thereof closes said ports so that no fluid will ow through the valve.

As shown in FIG. 8, the valve member 424 is normally spring-urged downwardly and the extension 431 thereof mounts a roller 432, which, when the rudder bar 400 is in neutral position, rests against the mid portion of the camming surface 433 of a cam 434 carried by shaft 401.

The end of extension 403 of the rudder bar 400 is pivoted as at 435 to the piston rod 436 of hydraulic actuator 437 which is pivoted to a xed support as at 438.

As is clearly shown in FIG. 8, with the rudder bar in neutral position, the pivotal axis dened by shaft 401 and the pivots 435, 438 are longitudinally aligned.

The actuator 437 has ports 441, 442 positioned respectively on each side of the piston 443 thereof, said ports being connected respectively to the ports 444, 445

- of a valve 446, the latter having three additional ports the inlet of which is connectedto said reservoir 453x The check valve 456 is designed to permit flow only from the pump to the accumulator and not in the reverse direction.

The valve 446 has control ports 458, 459 at its ends respectively which are connected by line 461 to ports 426, 428 of valve 425 and by line 462 to port 427 of said valve 425.

Operalion, FIG. 8

In the operation of the embodiment of FIG. 8, whichl is intended for small vessels, when the steering wheel is turned in direction to force fluid through line 415, such uid will enter port 409 of actuator 406 to move the piston rod 405 thereof outwardly thereby causing the 14 this occurs, the roller 432 rides up the camming surface 433 to lift the valve member 429 of valve 42S.

As a result, the ports 423, 427 and 424, 428 of valve 425 will be connected. Fluid under pressure will ow through line 462 into port 459 of valve 446 to lift the valve member 451 thereby connecting ports 448, 445 and 447, 444.

As a result of the connection of ports 448, 445, fluid under pressure will be supplied from accumulator 445 to port 442 of actuator 437 to force the piston rod 436 thereof outwardly. As the initial counterclockwise rotation of the rudder bar caused the actuator 437 to pivot in a clockwise direction, it will now be in a position such that outward movement of the piston rod thereof will apply considerable force against extension 403 of the rudder bar 400 to rotate the latter in such counterclockwise direction. y

As soon as the helmsman stops rotation of the steering wheel 418, flow of fluid through line 415 will close. Hence, no further fluid will be forced into actuator 406 or through valve 425 to port 459 of valve 446.

As a result, the upper spring 452 of valve 446 will move the valve member 451 thereof to closed position so that no further fluid under pressure will be applied to actuator I'437 from the accumulator 455.

Consequently, since the actuators' 406 and 437 `are no longer exerting force against the rudder bar 400, it will remain in its set position.

It is to be noted that as in the case of the other embodiments herein, when the steering wheel of the telemotor 417 is not rotated, suitable valves in the lines from the telemotor will close to block ilow of fluid in such lines.

As the roller 432 is resting on the cam 434, the valve member 429 of valve 425 will remain in its upper position.

It at this time the helmsman should wish to restore the rudder to neutral position he need merely rotate the steering wheel in the opposite direction so that fluid will ow through line 416.

As a result, the piston rod 405 of actuator 407 will be moved downwardly urging the rudder bar in a clockwise direction. In addition, fluid will initially flow through ports 424, 428 of valve 425 which are connected, so that it will enter port 45S of valve 446 to move the valve member 451 thereof downwardly to connect ports 448, 444 so that fluid under pressure will be applied from .accumulator 455 to port 441 of actuator 437. As a result, the piston rod 436 of actuator 437 will move downwardly to move the rudder bar in a clockwise direction toward neutral position.

As soon as the rudder bar approaches neutral position, the cam 434 will permit the valve member 429 to move downwardly closing the ports of valve 425 and hence permitting valve 446 to restore to neutral or closed position so that only the actuator 407 will be in circuit to finally move the rudder bar Vto its neutral position which will occur with substantially no over-shooting.

To move the rudderl in the opposite direction, the helmsman need merely continue the rotation of the steering wheel 418 and the operation previously. described,

f but with the valve member 429 moving downwardly will occur. y

It is to be noted that in all of the embodiments herein shown, the telemotor and associated hydraulic circuitry applies relatively low power to effect movement structions, and many apparently widely different -embodiments of this invention could be made Without-departing from the scope of the claims, it is intended that rudder bar to move'in a'counterclockwise direction. Asi l75 all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

Having thus described our invention, what we claim as new and desire tosecure by United' States Letters Patentis:

1. A hydraulic Acontrol vsystem for effecting rotary v ber on each side 'of its neutral position and means controlled'by the initial movement of said shaft away from its .neutral position -to actuate said' hydraulic actuator to apply-additional force to said shaft in the direction of such movement away from its neutral position.

2. Afhydraulic -control system' for Veiecting rotary .zrnovement of a movable An'iember on each-'side of a neutral position, said system comprising a hydraulichctuator operatively connected -to--said movable member, means initially-to effectY movement `of saidmovable member on each side of its neutral position, means controlled by the .initialrmovement of said movable member awayV from its neutral position to actuatesaid hydraulic actuator to apply additional force to said movable member in the direction ofsuch movement away from'its neutral position, a source of fluidunder pressure, a reversing valve .operatively connected to said source of uid under pressurev-and said-hydraulic actuator, the means controlled by the movement of said movable member away from its neutral position actuating lsaidvalve to apply' fluid yunderrpressureto Vsaid actuator in direction to'cause'he .actuator to react` against said movablernember in the direction of the movement of the'movable member away Vfrom its neutralA position.

"3. The combination set forth in claim'2 in which said reversingovalve has a movable valve member, a Vcam is l provided controlling said valve member, and means oper- V,a'tively yconnecting said cam to said movable member to I eiect movement of Asaid cam on movement ofk saidmov- Vable memberV away from fits' neutral position to actuate the valvemember of said reversing valve.

4. AV hydraulic control system lfor eiecting rotary 'movement of armovable member on each side offa neutral position, said system comprising a hydraulic actuator opery'atively connected to said, movable member, means initially toetectmovement of said movable member on each sidefof-its/neutral position, said means comprising an pair of servo-hydraulic actuators each comprising?L cylinder pivotally mounted at one end'to a fixed support,

i each of said actuators having a movable piston rod, rneansoperatively connecting said piston rods to said .j movable member, means'to apply uidunder pressurev .'tosaidfservoiactuators to effect initial-movement o-fk said movablemember away from its'neutral position on each ysidel thereof'frespectively,- and means controlled-by the initial movement of` said movable member away-from its neutral'posi-tion to actuate saidfhydraulic actuator to 4Vapply additional forceto said movable .member in `the direction of such movementaway from' its neutral position.

. f 5.]The combination, setforthv in claim ll in which -the means to apply'iiuidt under pressure toffsaid. servoA actu; i latorscornpris'es a telemotor having asteeiing wheel-and y uid pumps controlled'byxtherotation of said steering ,wheel selectively to apply such fluid. under vpressure to said servo actuators depend-ing upon the direction of rotation of'said steering-Wheel.

6. A hydraulic control system for effecting rotary movement of a movable member on each side of a neutral position, said system comprising a hydraulic actuator having a cylinder pivotally .mounted at one end to a fixed support and having said piston rod slidable therein, an arm rigidly connected to said shaft and extending at right angles thereto on each side thereof, means pivotally corineoting one end of said arm to the piston rod of said hydraulic actuator; the pivotal axis of said shaft, the pivotal connection of said piston rod to said arm and the xed pivotal mount of said cylinder being longitudinally aligned when said shaft is in neutral position,

means initially to effect movement of said movable member on each side of its neutral position, said means comprising a pair of servo hydraulic actuators each comprising a cylinder pivotally mounted at one end to a fixed support,-each ofsaid cylinders having a movable piston rod, means pivotally connecting the outer ends ot said piston rods to said arm on each side of said shaft equidistant respectively from said shaft, means alternately to apply fluid under pressure lto said servo actuators to effect initial movement of said shaft away from its neutral position on each side thereof respectively, and means controlled by the initialmovement of said movable member away from its neutral position to actuate said hydraulic actuator to apply additional force to said movable member in the direction of such movement away from its neutral position.

'7. A hydraulic control system for effecting rotary movement of a movable member on each side of a neutral position, said system comprising a hydraulic actuator' operatively connected to said movable member, a lirst source of fluid under pressure, means controlled by said first source of fluid under pressure initially to efect movement of said movable member on each side of its neutral position, a control valve, a second source of fluid under pressure controiledby said control valve, a reversing valve operatively connected to said control valve and said hydraulic actuator to control the direction of the iiow of uid from saidV secondsource through said control valve into said hydraulic actuator and means controlled by the initial movement of said movable member awayfrom its neutral position to actuate said reversing valve to apply fluid under pressure to said hydraulic actuator in direction to causesaid actuator to react against the movable member in the direction ofthe movement of said movable member away from its'neutral position,

8. The -combination set. forth in claim 7 in which said control valve is hydraulically actuated and is operatively connected to said rst'source Vof iiuid under pressure.

9. The combination set forth in claim 7 in which said control `valve is electrically actuated and a switch isproided to energize said control valve.

10. A hydraulic control system for effecting rotary movementof a shaft `on eachrside. of a neutral position,

' said system comprising a' hydraulic actuator comprising a cylinder pivotallyrrnounted at one end to a iixed support and having a 'piston Vrod slidable therein,-an arm rigidly connected to said shaft and extending yat right angles thereto on eachk side thereof,- means pivotally connecting one .end `of saidY arm tothe piston rod of said hydraulic actuator, the pivotal axis of said shaft, the

pivotal connection of said piston rod to said armr and the iixed lpivotal kmount of said cylinder being longitudinally aligned when said shaft is inA neutral position, a pair offservo hydraulic actuators each comprising a cylinder pivotally mounted at one end to a fixed support, each of said cylinders having` a movable piston rod pivotally .connected at vits `other end to saidv arm on each side of saidv shaft, equidistantfrespectively from .said-shaft, a first source of tiuid under pressure, means alternately to apply iiuid underpressure from said first source to said servo actuators kto effect initial movement of saidV shaft away .from `its neutralpo'sition on yeach side thereof respectively,

a controlrvalve, a'secon'd* source ofliuid under pressure controlled by said control valve, a reversing valve operatively connected -to said control valve and said hydraulic actuator to control the direction of the flow of fluid from said second source through said control valve into said hydraulic actuator and means controlled by the ini-tial movement of said shaft away from its neutral position to actuate said reversing valve to apply uid under pressure to said hydraulic actuator in direction to move the piston rod thereof in the direction of the movement of said shaft away from its neutral position.

11. The combination set forth in claim in which a pressure relief valve is connected to said hydraulic actuator.

12. The combination set forth in claim` 10 in which said con-trol valve is hydraulically actuated, said first source of fluid under pressure comprises a telemotor having a steering wheel and a fluid pump controlled by rotation of said steering wheel selectively to apply such iiuid under pressure to said servo actuator and to said control valve depending upon the direction of rotation of said steering Wheel.

13. The combination set forth in claim l2 in which pressure relief means are connected to said servo actuators.

14. A hydraulic control system for effecting rotary movement of a shaft on each side of a neutral position, said system comprising afirst and second hydraulic actuator each comprising a cylinder pivotally mounted at one end -to a fixed support and having a piston rod slidable thereon, an arm rigidly connected to said shaft at one end and extending at right angles thereto, means pivotally connecting the other end of said arm to the piston rod of said first actuator; the pivotal axis of said shaft, the pivotal connection of said piston rod to said arm and the fixed pivotal mount of said cylinder of said first actuator being longitudinally aligned when said shaft is in neutral position, a substantially L-shaped lever having a pair of arms, means pivotally mounting said lever, means pivotally connecting one end of one of the arms of sa-id lever to the piston rod of said second actuator, a link pivotally connected at one end to said shaft arm between its ends and at its other end to the pivotal connection of the lever arm to the piston rod, a pair of servo hydraulic actuators each comprising a cylinder pivotally mounted at one end to a fixed support, each of said cylinders having a movable piston rod pivotally connected at its outer end to the other arm of said lever on each side of its pivotal mount and equidistantly spaced from said mount, a first source of fluid under pressure, means alternately to apply fluid under pressure from said first source to said servo actuators to effect pivotal movement of said lever and said shaft arm and said shaft, from the neutral position of said shaft to either side respectively, a second source of fluid under pressure, a control valve, controlling said second source and the direction of flow of fluid from said second source to said second actuator, a reversing valve operatively connected between said control valve and said first actuator to control the direction of the ow of fluid from said second source through said control valve into said first actuator` and means controlled by the initial movement of said shaft away from its neutral position to actuate said reversing valve -to apply fluid under pressure to said first actuator in direction to move the piston rod thereof in the direction of the movement of said shaft away from its neutral position.

l5. The combination set forth in claim 14 in which means are provided to limit the angular movement of said shaft on each side of its neutral position.

16. The combination set forth in claim 14 in which means are provided to cut ofi flow of fiuid under pressure to said actuators when the shaft has rotated a predetermined amount on each side of its neutral position.

17. A hydraulic control system for effecting rotary movement of a shaft on each side of a neutral position,

said system comprising a pair of hydraulic actuators each comprising a cylinder pivotally mounted at one end to a fixed support and having a piston rod slidable therein, an arm rigidly connected to said shaft and extending at right angles thereto on each side thereof, means pivotally connecting one end of each of said piston rods to said arm on each side of said shaft and equidistantly spaced therefrom, an additional hydraulic actuator comprising a cylinder pivotally mounted at one end to a fixed support and having a piston rod slidable therein, means pivotally connecting one end of said arm to the piston rod of the additional actuator; the pivotal axis of said shaft, the pivotal connection of the piston rod of said additional actuator to said arm and the fixed pivotal mount of said additional actuator being longitudinally aligned when said shaft is in neutral position, a pair of ganged reversing valves adapted to move in unison and connected respectively between said first source of fluid under pressure and said pair of hydraulic actuators, means to actuate said reversing valves to apply fluid under pressure from said first source to said pair of hydraulic actuators to effect movement of said shaft from its neutral position, an additional reversing valve, and means controlled by the initial movement of said shaft away from its neutral position to actuate said additional reversing valve `to apply fluid under pressure to said additional hydraulic actuator in direction to move the piston rod thereof in the direction yof the movement of said shaft away from its neutral position.

18. The combination set forth in claim 17 in which a second source of fluid under pressure is provided, said reversing valves are hydraulically controlled, said second source of fluid is connected to said reversing valves and means are providedto direct such fluid into one or the other of said reversing valves.

19. The combination set forth in claim 17 in which electric drive means are provided to actuate said ganged reversing valves.

20. The combination set forth in claim 17 in which a bar is secured to said additional actuator and extends longitudinally thereof beyond the fixed pivot thereof, a pair of servo hydraulic actuators are provided each comprising a fixed cylinder and having a piston rod slidable therein, the ends of said piston rods being adapted to engage said bar on each side of` the fixed pivot thereof and equidistantly spaced therefrom, a second source of fluid under pressure is provided operatively connected to said servo actuators, and means alternately to apply fluid from said second source to said servo actuators to effect initial movement of said shaft.

21. The combination set for-th in claim 17 in which said first source of liuid comprises a reservoir having a partition therein defining two chambers, a pair of pumps having their inlets connected respectively to said chambers, a common line, the outlets of said pumps being connected to said common line, a normally open valve connected in said common line between said pump outlets, means when the level of the fiuid in the reservoir falls below a predetermined amount to close said valve, said common line on each side of said valve being connected respectively to said pair of reversing valves.

22. The combination set forth in claim 2l in which a pressure accumulator is provided, means to charge said accumulator and means to connect said accumulator into the hydraulic circuit to said reversing valves when the latter have been moved Ito fully open position.

23. A hydraulic system for effecting rotary movement of a shaft on each side of a neutral position, said system comprising a pair of hydraulic actuators each comprising a cylinder pivotallymounted at one end to a fixed support and having a piston rod slidable therein, an arm rigidly connected to said shaft and extending at right angles thereto on each side thereof, means pivotally connecting one end of each of said piston rods to said arm on each side of said shaft and equidistantly spaced there- 19 from an extension arm rigid with said shaft arm and extendingA at right angles thereto and aligned with the axis of said shaft, an additional hydraulic actuator comprising a cylinder pivotally mounted at one endV to a iixed support,V and having a piston rod slidable thereon, means pivotally connecting one end of said extension arm to the piston rod of the additional actuator; the pivotal axis of said shaft, the pivotal connection of the piston rod of said additional actuator to said extension arm and the iixed pivotal mount of said additional actuator being longitudinally aligned when said shaft is in neutral posi- Vtion, a iirst source of uid under pressure, a reversing valve connected between said source of iluid and said additional actuator and normally cutting off ow of fluid to said additional actuator when said shaft is in neutral position, a second source of fluid under pressure, a second reversing valve connected between said lirst reversing valve and said second source of iiuid under pressure, and means to apply uid from said second source to one of said pair of hydraulic actuators to effect initial movement of said shaft from its neutralposition and means controlled by thel initial movement of said shaft away from its neutral position to actuate said second reversing valve to permit flow of uid therethrough from said second source of lluid to said first reversing valve to actuate the latter tol connect said first source of uid to said additional actuator in direction to move the piston rod thereof in the direction of the movement of the shaft Vaway from its neutral position.

24. The combination set forthin claim 23 in which said lirst reversingl valve has aslidable valve member having an extension, a cam is movable with said shaft and engages said extension to effect movement of said slidable member upon rotation of said shafti 25. A hydraulic control system for eliecting movement of a movable member on each side of a neutral position comprising a telemotor connected through two pressure lines to hydraulic motor means operatively connected to said movable member, hydraulic servo-valve means responsive to the difference of pressure between said two pressure lines controlling the connections of a source of pressure toa second hydraulic motor means to apply additional force to said hydraulic motor means in the direction of they initial movement away from its neutral posi-tion, and a ,second independent telemotor, acting in the same direction as the first telemotor, said servo-valve means also being responsive to said second telemotor.

26. The combination set forth in claim 25, in which the second telernotor is also of the hydraulic type.

27. The combination set forth in claim 25, in which the second telemotor is of the electric type controlling solenoid means integrated within the hydraulic servovalve means.

28. The combination set forth in claim 25, in which the second telemotor is of the electric type, and comprises a reversible electric motor controlling two operatively connected hydraulic servo Valves, each controlling the connections of two independent sources of pressure to two independent hydraulic motor means.

References Cited in thele of this patent UNITED STATES PATENTS 2,859,592 Mercier et al. Nov. 1l, 1958 2,892,310 Mercier .Tune 30, 1959 3,009,322 Mercier Nov. 2l, 1961 FOREIGN PATENTS 1,203,051 France July 27, i959 

1. A HYDRAULIC CONTROL SYSTEM FOR EFFECTING ROTARY MOVEMENT OF A SHAFT ON EACH SIDE OF A NEUTRAL POSITION, SAID SYSTEM COMPRISING A HYDRAULIC ACTUATOR HAVING A CYLINDER PIVOTALLY MOUNTED AT ONE END TO A FIXED SUPPORT AND HAVING A PISTON ROD SLIDABLE THEREIN, AN ARM RIGIDLY CONNECTED TO SAID SHAFT AND EXTENDING AT RIGHT ANGLES THERETO, MEANS PIVOTALLY CONNECTING SAID ARM TO THE END OF SAID PISTON ROD; THE PIVOTAL AXIS OF SAID SHAFT, THE PIVOTAL CONNECTION OF SAID PISTON ROD TO SAID ARM AND THE FIXED PIVOTAL MOUNT OF SAID CYLINDER BEING LONGITUDINALLY ALIGNED WHEN SAID SHAFT IS IN NEUTRAL POSITION, MEANS INITIALLY TO EFFECT MOVEMENT OF SAID MOVABLE MEMBER ON EACH SIDE OF ITS NEUTRAL POSITION AND MEANS CONTROLLED BY THE INITIAL MOVEMENT OF SAID SHAFT AWAY FROM ITS NEUTRAL POSITION TO ACTUATE SAID HYDRAULIC ACTUATOR TO APPLY ADDITIONAL FORCE TO SAID SHAFT IN THE DIRECTION OF SUCH MOVEMENT AWAY FROM ITS NEUTRAL POSITION. 